Men with deeper voices have an advantage in attracting women, but mostly if they’re looking for a fling, new research suggests.

Researchers at at McMaster University in Ontario, Canada have previously reported on the link between the depth of a guy’s voice and his attractiveness to women. They also figured that guys with lower voices, and hence probably more testosterone, were more likely to cheat (they were right). What they couldn’t work out was why women preferred the men who were probably going to be cads. So they went back to the audiotape.

In the new study — which may also provide some insight into why Isaac Hayes songs are forever a popular choice for the boudoir — researchers had women listen to men’s voices and asked them first if they thought the speaker was a faithful sort of guy. Then they were asked if they fancied the owner of the voice for a long or short-term relationship. The deep-voiced men were chosen more often for short term relationships, but mostly by certain sorts of women—those who had already expressed a belief that a bass voice often led to fishy behavior.

“Differences in the strength of women’s preferences were accounted for by whether or not they thought the voices belonged to a cheater,” says Jillian O’Connor, a postdoctoral fellow in the Department of Psychology, Neuroscience and Behaviour at McMaster, who was this study’s (and the prior one’s) lead author. “Women who thought that men with lower pitched voices were cheaters liked them for short-term flings.” The scientists defined “short-term relationship” more towards the one-night-stand than the May to December fling.

The women who didn’t associate a deep pitch with infidelity tended to prefer those guys for long term relationships. The authors surmised that some women have come to adaptively understand that more macho guys are more likely to cheat — and have thus learned to avoid macho-sounding guys for serious life partnering.

For deep-voiced males, fear not. The study was pretty small, just 87 women, and it didn’t use actual tones. The voices the women heard came from the same guy with his pitch digitally deepened or heightened. Which means the findings probably aren’t conclusive enough to cross off any baritones from anybody’s list of eligible bachelors, even if biology were destiny.

The lure for a deep voice for females may have something to do with the woman’s biology too. “Some of my other research has found that women who have more attractive faces have stronger preferences for lower pitched men’s voices,” says O’Connor. “But that was not examined in this study.” Looks like men are not the only ones who respond to siren songs.